Radioiodinated Phenylalkyl Malonic Acid Derivatives as pH-Sensitive SPECT Tracers

pH imaging has been a field of interest for molecular imaging for many years. This is especially important for determining tumor acidity, an important driving force of tumor invasion and metastasis formation, but also in the process of apoptosis.I]IPM was evaluated in an anti-Fas monoclonal antibody (mAb) apoptosis model. In addition a mouse RIF-1 tumor model was explored in which tumor pH was decreased from 7.0 to 6.5 by means of induction of hyperglycemia in combination with administration of meta-iodobenzylguanidine.I]IPM showed a clear pH-related uptake pattern in the RIF-1 tumor model. which allows to visualize regional acidosis. However, these compounds are not suitable for detection of apoptosis due to a poor acidosis effect

Preference elicitation techniques for group recommender systems

A key issue in group recommendation is how to combine the individual preferences of different users that form a group and elicit a profile that accurately reflects the tastes of all members in the group. Most Group Recommender Systems (GRSs) make use of some sort of method for aggregating the preference models of individual users to elicit a recommendation that is satisfactory for the whole group. In general, most GRSs offer good results, but each of them have only been tested in one application domain. This paper describes a domain-independent GRS that has been used in two different application domains. In order to create the group preference model, we select two techniques that are widely used in other GRSs and we compare them with two novel techniques. Our aim is to come up with a model that weighs the preferences of all the individuals to the same extent in such a way that no member in the group is particularly satisfied or dissatisfied with the final recommendations. © 2011 Elsevier Inc. All rights reserved.Partial support provided by Consolider Ingenio 2010 CSD2007-00022, Spanish Government Project MICINN TIN2008-6701-C03-01 and Valencian Government Project Prometeo 2008/051. FPU grant reference AP2009-1896 awarded to Sergio Pajares-Ferrando.García García, I.; Pajares Ferrando, S.; Sebastiá Tarín, L.; Onaindia De La Rivaherrera, E. (2012). Preference elicitation techniques for group recommender systems. Information Sciences. 189:155-175. https://doi.org/10.1016/j.ins.2011.11.037S15517518

Exemplary UV- (top) and radiochromatogram (bottom) of reaction mixture after radioiodination of IPMM (60 min reaction time, 90°C, 1 mg precursor).

<p>In the UV signal, gentisic acid (Rt: 10 min), IPMM (Rt: 15 min) and IPMM diethyl ester (R_t: 16 min) can be identified. In the radiochromatogram, ¹²³I-labeled IPMM and ¹²³I-labeled IPMM diethyl ester can be seen, as well as an unidentified side compound (R_t: 7 min).</p

Uptake of ¹²³I-labeled IPM in Jurkat cells after 3 h incubation in phosphate buffered NaCl or phosphate buffered KCl solutions as a function of in situ pH.

<p>The [IPM^−/[IPM²⁻] ratio is shown for comparison (dotted line).</p

Uptake of ¹²³I-labeled IPMM, IBMM, IP and IPM in Jurkat cells in control conditions, with anti-fas mAb induced apoptosis, incubated in KCl-solution and with freeze-thaw induced necrosis.

<p>Uptake of ¹²³I-labeled IPMM, IBMM, IP and IPM in Jurkat cells in control conditions, with anti-fas mAb induced apoptosis, incubated in KCl-solution and with freeze-thaw induced necrosis.</p

Biodistribution of ¹²³I-labeled IPMM and IPM in healthy NMRI mice, 60 min p.i.

<p>Biodistribution of ¹²³I-labeled IPMM and IPM in healthy NMRI mice, 60 min p.i.</p

SPECT/CT image of [¹²³I]-labeled IPM in healthy NMRI mice, acquired between 45–80 min p.i. (summed image).

<p>(A) Coronal section of the mouse body (head not included), showing high uptake in bladder and heart (blood pool). (B) Transversal section of the mouse in the heart region. (C) Transversal section showing bladder activity.</p